Electrical communication network



Naval, 1938. H. R. ALLEN$WORTH 2,134,690

' Y ELECTRICAL COMMUNICATION NETWORK Filed Oct. 9, 1936 HARRY R ALLENSWOR TH I INVENTOR ATTORNEY Patented Nov. 1, 1938 UNITED STATES PATENT OFFICE Application October 9,

15 Claims.

My invention relates to a new and improved electrical communication network and more particularly to a communication network, or that part of a communication network comprising a 5.. telephone transmitter, a telephone receiver, a transformer (induction coil) and a condenser (capacitor) and has for its object a new and improved combination o-f these elements in an electric network, functioning by means of electro- 10 motive force, the source of which electromotive force is external to the electric network comprising the said telephone transmitter, receiver, transformer and condenser.

A conventional telephone network comprises a 15. three winding transformer (induction coil) a transmitter, condenser (capacitor) and an inductively coupled receiver together with suitable switches and signalling and calling devices. The condenser and two windings of the transformer are in seriesone of which two windings being connected across the terminals of the transmitter, directly on one side and in series with the condenser on the other. The third winding together with the receiver in series form an inductively coupled secondary circuit.

To my knowledge there has not-been prior to my invention an electrical communication network, telephonic or otherwise, comprising four transformer windings-three of said windings being primary to the fourth-a telephone transmitter, a telephone receiver, and a condenser; said network being divided into two parallel circuits bridged by a condenser,

r The accompanying drawing is a schematic delineation, by means of conventional symbols, of

a useful and practical application of my invention in the form of atelephone subscribers station network comprising seven members or parts to wit; a source of electromotive force-here represented by two sides of a line, L! and L2; a telephone transmitter T; transformer windings P l, P2 and P3; a condenser C and an inductively coupled secondary circuit comprising transformer 5 winding S and telephone receiver R. Also are shown, by means of conventional symbols, calling device CD with associated shunt contacts SH, polarized ringer or bell B in series with condenser Cl and hook switch HS with associated contact springs 8 and 9. Calling device CD with associated shunts, ringer B and hook switch HS are not, per se, a part of my invention. .Calling device CD with associated shunt contacts is shown for the purpose of revealing certain important characteristics of the network. Hook switch HS and 1936, Serial No; 104,857

polarized ringer B are shown for the purpose of explaining the function and action of contact springs 8 and 9.

The source of electromotive force LI and L2 may be a telephone line terminating in a common battery telephone switchboard or other common battery switching mechanism-it may be a circuit to another telephone not connected to'or with an exchange system, in which case electromotive force is impressed on the circuit at some convenient point external to the network herein described--it may be a telegraph or other signal circuit-it may be any suitable electric circuit which it may be practicable to employ for telephonic purposes by means of the network herein described.

Electromotive force from the source LI and L2 is impressed on the circuit or network at points 4 and 5 causing electric current to flow through the circuit, which current will divide at the points 20 4 and 5--part flowing through Pl, P3 and part through P2, T. The divided circuit 4, Pl, P3, 5; 4, P2, T,5 is bridged by a condenser C at points 6 and I.

All four transformer windings Pl, P2, P3 and S are on the same magnetic core.

The operation of this circuit or network during speech transmission is as follows.

The line circuit Ll, L2 which supplies direct current from a central oifice battery or other suitable source, divides into two parallel circuits at points 4 and 5; one of the two parallel circuits comprising transmitter T and P2 in seriesthe other, comprising Pi and P3 in series. The combined resistance of these two parallel circuits will be always less than the resistance of either.

Another circuit, local to the network, comprises transmitter T, condenser C and transformer winding P3.

When the transmitter T functions in response to sound waves, corresponding potential undulations are produced directly in the line through transmitter T and winding P2. Condenser C is connected across the terminals of transmitter T directly on one side and through winding P3 on the other. Condenser C charges and discharges due to varying potential drop across transmitter T. This causes P3 and PI to function as an auto transformer in which circumstance P! is second- 50 ary to P3. The current flowing in the said local circuit divides at the point 1; part flowing through P3 and part through PI. Thus the inductive effect of P3 on S is neutralized more or less depending on the relative proportions of PI, P2 and 55 P3; an effect known to the art as anti-sidetone. Also, Pl functions as an inductively coupled feed back on P2 producing improved booster characteristics in the network.

When the transmitter at the distant station functions, potential undulations from LI and L2 are impressed at points 4 and 5 in which circumstance Pl, P2 and P3 are primary to S and corresponding alternating E. M. F. is induced in S causing alternating current to flow in S and receiver R.

When calling device CD is operated-associated shunt contacts SH close, shunting trans-- mitter T and transformer winding S. PI and P3 being in parallel with P2, the resistance of the network to current impulses produced by calling device CD will be always less than the resistance of winding P2. Inasmuch as S issecondary to PI, P2 and P3shunting S during the operation of CD lessens the impedance of PI, P2 and P3 to current impulses produced by CD.

Condenser C is shown bridging the network at points 6 and I. Condenser Cl is shown in series with polarized ringer or bell B bridging LI and L2. It is not necessary" to employ two condensers in the network: Substituting C2 for C and Clwhen hook switch HS is down contact springs 8 and 9 put C2 inseries with B across LI and L2. When HS is up, C2, by means of 8 and 9, bridges the network at points 6 and l as shown by broken: lines on the accompanying drawing.

Thus the said seven members or parts as assembled and combined in my invention effect the following improved results over other such networks; lessened ohmic resistance to line current, lessened impedance to dialing impulses, improved booster effect together with anti-sidetone characteristics and high fidelity transmission and reception.

I claim:

1. An electricalcommunication network comprising two parallel circuits, one of. the two parallel circuits comprising a telephone transmitter in series with one winding of a transformer having four windings, one of the said parallel circuits comprising two of said windings in series, and a condenser bridging said circuits from a point between the transmitter and transformer winding in one of said parallel circuits to a point between the two transformer'windings in the other of the said parallel circuits.

2. An electrical communication network comprising two parallel circuits, one of the said parallel circuits comprising a telephone transmitter in series with one winding of a transformer having four windingsone of the two parallel circuits comprising two of said windings in series and a telephone receiver in series with a fourth winding forming an inductively coupled circuit, secondary to the three said transformer windings.

3. An electrical communication network comprising two parallel circuits and a condenser bridging said circuits, circuit make and break devices, a signal circuit, said circuit make and break devices being so disposed as to transfer said condenser from a bridge circuit between the said two parallel circuits to a signal circuit and vice versa.

4. An electrical communication network comprising two parallel circuits, one of the two parallel circuits comprising a telephone transmitter in series with one winding of a transformer having four windings, one of the said parallel circuits comprising two of said windings in series; the total resistance of said two parallel circuits being less than the resistance of the said transmitter and the transformer winding with which said transmitter is connected in series.

5. An electrical communication network comprising two parallel circuits, one of the two parallel circuits comprising a. telephone transmitter in series with one winding of a transformer having four windings, one of the said parallel circuits comprising two of said windings in series, the total resistance of said parallel circuits with the said transmitter shunted being less than the said transformer Winding with which said transmitter is normally in series.

6. An electrical communication network comprising two parallel circuits and four transformer windings, the total impedance offered by said parallel circuits to pulsating current set up in. the network being reduced by short circuiting a transformer winding said transformer winding being secondary to three transformer windings comprised in the said two parallel circuits through which said pulsating current passes.

7. An electrical communication network in which both anti-sidetone and booster characteristics are incorporated by dividing the said circuit or network into two parallel circuits, one of which parallel circuits comprises a telephone transmitter in series with one winding of a transformer having four windings, one of which parallel circui s comprises two of. said windings in series, and a condenser bridging said circuits at points of approximately equal potentials.

8. An electrical communication network comprising two parallel circuits, one of the two parallel circuits comprising a telephone transmitter in series with one winding of a transformer having four windings, one of the said parallel circuits comprising two of said windings in series, the total impedance offered by said parallel circuits to pulsating current set up in said network being reduced by short circuiting a transformer winding, said short circuited transformer winding being secondary to the three said transformer windings comprised in the said two parallel circuits through which said pulsating current passes.

9. An. electrical communication network comprising two parallel circuits and a' condenser bridging said circuits, one of the two parallel circuits comprising a telephone transmitter in series with one winding of a transformer having four windings, one of said parallel circuits comprising two of said windings in series, the total impedance offered by said parallel circuits to pulsating current set up in said network being reduced by short circuiting a transformer winding, said short circuited transformer winding being secondary to the three said transformer windings comprised in the two parallel circuits through which said pulsating current passes.

10. An electrical communication network comprising two parallel circuits and a condenser bridging said circuits at points of approximately equal potentials, one of the two parallel circuits comprising a telephone transmitter in series with one winding of a transformer having four windings, one of said parallel circuits comprising two of said windings in series, the total impedance offered by said parallel circuits to pulsating current set up in said network being reduced by short circuiting a transformer winding, said short circuited transformer winding being secondary to the three transformer windings comprised in the two said parallel circuits through Which pulsating current passes.

11. An electrical communication network comprising two parallel circuits and a condenser bridging said circuits, circuit make and break devices, a signal circuit, said circuit make and break devices being so disposed as to transfer said condenser from a bridge circuit between the said two parallel circuits to a signal circuit and vice versa, one of the two parallel circuits comprising a telephone transmitter in series with one winding of a transformer having four windings, one of said parallel circuits comprising two of said windings in series, the total impedance ofiered by said parallel circuits to pulsating current set up in said network being reduced by short circuiting a transformer winding, said short circuited transformer winding being secondary to the said three transformer windings comprised in the said two parallel circuits through which said pulsating current passes.

12. An electrical communication network comprising two parallel circuits, one of the two parallel circuits comprising a telephone transmitter in series with one winding of a transformer having four windings, one of said parallel circuits comprising two of said windings in series, the total resistance of said parallel circuits with said transmitter shunted being less than the said transformer winding with which said transmitter is normally in series, and the total resistance of said two parallel circuits being less than the resistance of the said transmitter and the transformer winding with which said transmitter is connected in series.

13. An electrical communication network comprising two parallel circuits, and a condenser bridging said circuits, one of said parallel circuits comprising a telephone transmitter in series with one winding of a transformer having four windings, one of said parallel circuits comprising two of said windings in series and a telephone receiver in series with a fourth winding forming an inductively coupled circuit, secondary to the said three transformer windings.

14. An electrical communication network comprising two parallel circuits and a condenser bridging said circuits, one of the two parallel circuits comprising a telephone transmitter in series with one winding of a transformer having four windings, and one of said parallel circuits comprising two of said windings in series, the three windings in the said parallel circuits being primary to a fourth connected directly to a telephone receiver.

15. An electrical communication network comprising two parallel circuits, one of the two parallel circuits comprising a telephone transmitter in series with one winding of a transformer having four windings, one of said parallel circuits comprising two of said windings in series, the total resistance of said parallel circuits with said transmitter shunted being less than the said transformer winding with which said transmitter is normally in series.

HARRY R. ALLENSWORTH. 

